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Old 27th October 2012, 06:16 PM   #1
kctess5 is offline kctess5  United States
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Default F.A.S.T. Woofer

I am in the process of gathering the parts to make myself a set of bookshelf speakers for college.

I want to go fully sealed FAST to get the highest quality sound possible, and the enclosure leaves about .25 cubic ft of space for the mid-bass woofers. This limits my selection quite a lot, I have narrowed it down to the following:

2 per speaker Silver Flute W17's

OR

Tang Band W8-1747 8" Aluminum Cone Subwoofer 264-855

OR

Tang Band W8-740P 8" Subwoofer 264-854


I will have Minidsp to linkwitz transform any of them that I choose. XO approx 300 Hz. I will probably have a sub but want these to sound good even without one

Here are my criteria (in this order):
Sound quality
Depth extension

I choose the Silver Flute because it I think would have the best sound quality and is the most efficient. With 4 of them I would have plenty of displacement to linkwitz transfo down to 40Hz

The Tang Bands would go VERY deep in small enclosures (f3 50-60 f10 35hz) but I am worried that the 70 gram moving mass will make for very mushy bass.

Which would you choose and why?
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Old 27th October 2012, 09:54 PM   #2
sreten is offline sreten  United Kingdom
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Hi,

MCM Audio Select 8'' High Excursion Woofer - 120W RMS 4ohm | 55-2421 (552421) | MCM Audio Select ,

rgds, sreten.

8 mm Xmax one way ! (24mm coil, 8mm gap), will work in 7L, great value.
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Last edited by sreten; 27th October 2012 at 09:58 PM.
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Old 27th October 2012, 10:31 PM   #3
kctess5 is offline kctess5  United States
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Any idea how it sounds? I always wonder about foam surrounds these days...

It looks perfect SPL wise. That's a great find thanks!
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Old 27th October 2012, 11:57 PM   #4
sreten is offline sreten  United Kingdom
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Hi,

No idea what it sounds like, as I generally don't with any bass unit,
though I suspect you can do better for a lot more, distortion wise.

rgds, sreten.
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Old 28th October 2012, 06:11 AM   #5
kctess5 is offline kctess5  United States
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One nice thing about those Silver Flutes is their incredibly low distortion (measurements on zaph). They are pretty cheap too which is nice so I could get 4 of them. Do you think with linkwitz transform I could get them low enough that they wouldn't need a sub without too much trouble?
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Old 28th October 2012, 06:32 AM   #6
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With the LT you're gonna force them to work on their lowest frequency
allowed capability ...and, as they are not claimed to be subs they're gonna
distort ! But...it depends of which speaker is supposed to be put 'above' .
With two speakers you're gonna get double distortion .
Which is not properly distortion: maybe you'll hear the sound of the cone flapping but producing no sounding (musically speaking) output .
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Old 28th October 2012, 07:05 AM   #7
kctess5 is offline kctess5  United States
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Quote:
Originally Posted by picowallspeaker View Post
With the LT you're gonna force them to work on their lowest frequency
allowed capability ...and, as they are not claimed to be subs they're gonna
distort !
Click the image to open in full size.

It appears to me that the distortion at 40Hz is approx 40dB down from the fundamental. That doesn't seem all that bad to me. Assuming I stay within the 5mm xmax (about 102 dB @ 40Hz w/ 4 woofers) then it seems that distortion should be at that level.

Quote:
With two speakers you're gonna get double distortion .
Which is not properly distortion: maybe you'll hear the sound of the cone flapping but producing no sounding (musically speaking) output .
How do you figure? I would say that two speakers per box = less distortion because there would be less excursion for each woofer. It seems the only time they would be audibly flapping is when they are over x-max which is not what I intend.

My target is 40Hz, so I would LT down to that and then use a high order high pass at 38 or so Hz. I think if they can get to 40 they will sound good without a sub but will still benefit when I eventually add one
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Old 28th October 2012, 07:26 AM   #8
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Mmmhh...reasoning by numbers may lead to conclusions that are
very stringent...and cruel !
I usually avoid ...and lucky me that I passed the age of hi-fi electronic music
with thumping bass . So now I'm centered to optimum mid-band, centre
indeed, ...yes!
BTW I did put a little PCB with LT inside my amp and left it in there for over
a year Was I ...biased ?
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Old 28th October 2012, 03:27 PM   #9
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I've used the SF17. I would caution you in your application to consider the power requirements to LT those drivers down to 40hz. I measure a pair in 15L (I can't remember the exact enclosure size, maybe only 12L) to only get down to around 80hz. To LT 12db back in at 40hz will require absurd power. Unless you listen quitly or the near field.

The second thing I'll say about the driver is that it's got a very unique set of properties. Effecient, good sealed, good price, extended up high... You touched on some of these. Listening impressions for me are that it is very forgiving and very easy to work with. Doesn't do anything wrong.

In your application I'd look for something metal and less effecient with more bass extension. Unless you plan to add subs soon and for certain.
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Old 28th October 2012, 03:36 PM   #10
kctess5 is offline kctess5  United States
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Quote:
Originally Posted by tuxedocivic View Post
I've used the SF17. I would caution you in your application to consider the power requirements to LT those drivers down to 40hz. I measure a pair in 15L (I can't remember the exact enclosure size, maybe only 12L) to only get down to around 80hz. To LT 12db back in at 40hz will require absurd power. Unless you listen quitly or the near field.

The second thing I'll say about the driver is that it's got a very unique set of properties. Effecient, good sealed, good price, extended up high... You touched on some of these. Listening impressions for me are that it is very forgiving and very easy to work with. Doesn't do anything wrong.

In your application I'd look for something metal and less effecient with more bass extension. Unless you plan to add subs soon and for certain.
What if I didn't go for a totally flat response to 40, say -3db at 50 and -6 at 40. That would still be quite audible and require much less power. That would put them around 85dB 1 watt. I have 2 100w amps for them, one per pair.

Given those issues would you recommend the Tang Band 1747? It seems to fit your criteria well.
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